Department of Otolaryngology, College of Medicine, Busan National University, Korea

各種 詐聽檢査法의 臨床的 硏究

李鍾澹

釜山大學校 醫科大學 耳鼻咽喉科學敎室

ABSTRACT

Author have studied the malingering test of hearing with arbitrary repeated pure tone audiometry. Arbitrary Bekesy audiometry and delayed auditory feedback method (DAF), for the purpose of evalualuation of most reliable malingering test and its normal range. The subjects were 62 cases with normal hearing who were asked to try intentionally as moderate or high degree of hearing loss and measured this arbitrary threshold 3 times with one week interval. The arbitrary threshold gap was evaluated in each threshold which obtained from first-second and first-third measurement in each frequency and characteristic type of that audiogram was evaluated. The Bekesy audiometry was performed, as being designed moderate or high degree of hearing loss, with continous and interrupted tone in fixed frequency at 500 Hz, 1000 Hz, and 4000 Hz, and evaluated configuration of that Bekesy audiogram and threshold gap between first measurement of pure tone arbitrary threshold and this Bekesy tracing. To the person who was already tested, the delay auditory feedback recording (DAF) was done by key tapping with his index finger three times continuously and was repeated after short time lapse, and then the level of confusion of tapping number or interval was regarded as DAF threshold. The results were obtained as follows: 1) The average arbitrary threshold gap between first and second hearing threshold was seen in range from 6.6 dB to 11.7 dB, and 50 to 60% were the mistaken cases as normal value or test error within the gap of 5 dB. 2) The configuration of pure tone audiogram to be asked for the intentional try on showed that so-called Saucer type was 20 cases of 48 cases, 41.7% and was the highest percentage, but that was no aid for evaluation of the malingering hearing. 3) The average threshold gap, which was observed between pure tone arbitrary threshold and Bekesy tracing at 500 Hz and 1000 Hz, was disclosed in range from 6.7 dB to 15.4 dB and the gap was wider than the average arbitary threshold gap between first and second hearing threshold. 37.0% were the mistaken cases as normal value or test error within the gap of 5 dB. 4) 14.3% were the cases that both the gap of the Bekesy tracing and the average arbitrary threshold gap between first and second hearing threshold were within 5 dB at the same cases above. 5) The frequency of Bekesy audiogram type V tracing was seen in 24 cases of 36 cases, 66.6% a 500 Hz, and 13 cases, 36.1% at 1000 Hz. Abnormal amplitude were 16 cases, 44.4% at 500 Hz and 15 cases, 41.7% at 1000 Hz. Malingering hearing could be evaluated with 88.9% in regard of the Bekesy audiogram type V tracing and abnormal amplitude. 6) The average threshold gap between DAF threshold and normal true hearing was seen in 16.4 dB at 500 Hz, 17.2 dB at 1000 Hz, 20.9 dB at 4000 Hz. This result can te the guideline for the evaluation of the original hearing threshold. 7) DAF method posesses the character of the objectiveness and revival without and disability of observation in the test of the malingering hearing, it is the best method, however, it has a slight difficulty in evaluation of the original hearing. Author concluded that the combination of the above commented methods increased the confidence ratio and the most reliable test evaluation of the malingering hearing was DAF method.